If I understood correctly, this project is NOT an extension, but rather version of Yii with AWS features built-in? Is that right?

Could you explain why going this route vs extension?

Also, what are the features? The website doesn't say much yet.

You are right. This is not a plugin. This is YII that includes the libraries for using AWS. I wish you the best of lucks with your project!

The idea of using this instead of an extention is that in the near future ( I think & hope ) they will be examples using all the stuff from amazon. Is just a different approach. Just choose the want that is best for you.